01 - Preheat oven to 350°F. Generously grease and flour a 10-cup Bundt pan, ensuring every crevice is coated to prevent sticking.
02 - In a medium bowl, sift together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt. Set aside.
03 - In a large bowl, beat the room-temperature butter and granulated sugar using an electric mixer until pale, light, and fluffy, approximately 3 minutes. Add the eggs one at a time, beating thoroughly after each addition. Blend in the vanilla extract.
04 - Alternately add the sifted flour mixture and buttermilk to the butter mixture, beginning and ending with the dry ingredients. Fold gently until just combined — avoid overmixing to keep the crumb tender.
05 - Pour the batter evenly into the prepared Bundt pan, smoothing the surface with a spatula to ensure an even bake.
06 - Bake on the center rack for 45–50 minutes, or until a wooden skewer inserted into the thickest part of the cake emerges clean.
07 - Let the cake rest in the pan for 15 minutes, then carefully invert onto a wire cooling rack. Allow to cool completely before glazing.
08 - In a small saucepan, heat the heavy cream over medium-low until just steaming — do not boil. Pour the hot cream over the chocolate chips and butter in a heatproof bowl. Let stand for 2 minutes, then whisk until glossy and smooth.
09 - Drizzle the chocolate glaze over the completely cooled cake, allowing it to flow naturally down the sides for an elegant drip effect.
10 - Lightly dampen the fresh cranberries with water, then roll them in granulated sugar until evenly coated. Let them dry on a wire rack. Arrange the sugared cranberries and rosemary sprigs around the top of the cake to mimic a wreath. Finish with a light dusting of powdered sugar for a snowy finish.